I think that has been wilfully ignored for the sake of people buying into their own arguments about Theo being inadequate in a number of ways. Let's be honest, in all likelihood the contract talks have played a major part in why Theo hasn't played more and as you just mentioned Wenger has previous on this. The longer it continues the more patently obvious it is that the contract talks are a factor. Why anybody would behave as if it is irrelevant by now is strange....
Now we have a few decent players, people are yelling, SELL HIM. As Emirates gooner says, a fanciful swap with Sterling poses the same problem as Sterling himself wants BIG wages and he has proven no more at the top level than Walcott has.
The Saga has been drawn out this long and it was the last time because Arsenal know getting a Walcott replacement is neither easy nor cheap and Theo knows finding another club who will pay him handsomely and represent a decent chance at the 1st team won't be easy either. Liverpool is no quick fix to the situation, the saga will continue and there will be those who will have us believe that Theo continues not to be played because Wenger has suddenly woke up to the fact that Theo isn't very good.
Chamberlain and Gnabry still have to prove their consistent quality as well as their fitness. Those basing arguments around Theo's injury record should be reminded of the fact that Chamberlain and Gnabry haven't exactly had injury free Arsenal careers either.